Spring for timepieces.



W. v. BOLTON.

SPRING FOR TIMEPIEGBS. APPLICATION FILED FEB. 1'7 1905.

Patented Jam 18, 1910.

' (gm-v0 who? W W d y 315 W der 1121 J ment of the iron group.

' UNITED STATES PATENT OFFICE.

WERNER V.

BOLTON, OF CHARLOTTENBURG, GERMANY, ASSIGNOR 'ro' SIEMENS HALSKEAKTIENGESELLSCHAFT, 0F BERLIN, GERMANY.

SPRING FOR TIMEPIECES.

Specification of Letters Patent.

Patented Jan. 18, 1910.

Application filed February 17, 1905. Serial No. 246,189. i

To all whom it may concern:

Be it known that I, \VnnNEn voN BOLTON, a subject of the Czar of Russia,and resident of Charlottenburg, near Berlin, Germany, have inventedcertain new and useful Improvements in Springs for Timepieces, of whichthe following isa specification.

The present invention relates to an improved construction of springs andmore particularly to springs which are employed intime pieces.Heretofore springs of this character have generally been made of steel,due to the fact that that material combines a great many advantageous prerties, such as being capable of easy manu acture, considcrablestrength, resistance to wear and the like. There are, however, certaininherent objections to the use of steel in springs for time pieces. Thismaterial is not permanent under all conditions and be ing susceptible tomagnetism, rust and wear, it often proves unsatisfactory. Prior to myinvention, however, so faras I am aware, no efficient substitute forsteel was suggested, and I therefore believe that I am the first toovercome these difliculties and .to provide a spring for time pieceswhich is capable of answering the severe requirements which aredemanded. In accordance with my invention, the spring contains tantalumpreferably combined wlth a hardening agent. In'niy application, SerialNo. 278,023, filed June 8, 1907, I claim the construction of springs fortime pieces-composed of tantalum, and in my application Serial No.278,024, filed June 8,

10.07, I claim the construction of springs for time pieces containingtantalum and an ele- The elements of the iron group are hardeningagents, and these come within the broader terms of the presentapplication, which relates to the use of tantalum with hardening agentsin gen eral, while 5 ecifically the present application relates urtherto the use of tantalum with hardening agents whose atomic weights areless than thirty. This includes the employment of carbon, oxygen, hydroen, silicon, boron and aluminum as the her ening agents.

Tantalum has. been proposed for use in.

filaments, for electric lighting in which its high meltin point is thechief ropertyutilized. I have found, however, t at tantalum possesses agreat many properties action of most acids.

which were not heretofore utilized, and which are of especial advantagein the springs of time pieces. It possesses, like steel, the property ofbeing easily worked and hardened. It offers greater resistance v tofracture than steel and it has great resiliency and elasticity. Itshardness can be increased to such a degree as to greatly exceeds that ofthe best steel, and it almost equals-the diamond in its hardness. It hasthe further advantage over steel in being one of the precious metalswhich is not affected by the atmosphere and which at ordinarytemperatures completely resists the A further important advantage whichit possesses is that it is non-magnetic or substantially so. Beingextremely hard, it has very great resistance to Wear, and beingresilient and elastic, while at the same time possessing great strength,it has the yielding property of steel with less liability to fracture;being non-magneticand resistant to acids and to the atmosphere, it has apermanence which steel entirely lacks. Having a very high melting point,it .is capable of use at temperatures beyond those at which steel wouldbe of service.

In the accompanying drawing I have shown an example of my invention.Sald drawing illustrates conventionally a clock spring composed oftantalum or a tantalum compound.

In order to work the metal satisfactorily, it must be previously wellfused- Th s is preferably done by heating the metal in a vacuum byelectrical means, such as electrical resistance or directly. by passingan carefully reheated or annealed in order to be rendered soft again. Inthis annealing process, care must be taken that the temperature does notrise too high as otherwise the metal is more easily attacked by theoxygen of the atmosphere. Even in the form of the finest drawn wire orthe thinnest rolled bands, however, the metal will stand a heating inthe open air up to a dark red heat without being appreciably affected.When so heated, the metal shows a coloring similar to tempered steel. Inorder to prevent too great a heating, especially when working with fineparts of pure tantalum, it is preferable to eileet the heatingindirectly by bringing large plates or drums to the temperature to whichthe parts to be heated are required to be brought, and then to bring theobjects of tantalum to beheated in contact with these plates or drums.If on the other hand, it is desired to raise the objeets of tantalum tohigher temperatures without their being materially afiected on theirsurfaces, it-is adyantageous to effect the heating in a vacuum as atvery high temperatures pure tantalum combines with almost all knownsubstances.

For imparting great hardness to the tantalum, any of the hardeningagents above mentioned or titanium and tin may be employed. Theiremployment may be in any of the ways well known to those skilled in thisart, for example, the object of tantalum to be hardened may be embeddedin carbon and then heated to redness. In the case of carbon, thetantalum becomes very hard and resistant as soon as a small per cent. istaken up. Also of the other named substances, only small quantities arerequired in order to produce great hardness. If the adceases tle that nofurther working of the same is possible.

I claim:

1. As a new article of manufacture, a spring for time pieces. containingtantalum.

2. As a new article of manufacture, a spring for time pieces. containingtantalum and a hardening agent.

3. As a new article of mamil'm-lure. a spring for time pieces containingtantalum and a hardening agent whose atomic weight is less than 30.

'4. As a new article of manufacture. a spring for time pieces composedof tantalum and a hardening agent.

As a new article of manufacture. a spring for time pieces composed oftantalum and a hardening agent Whose atomic weight is less than 30.

6. As an article of manufacture, a spring for time pieces containingtantalum and carbon.

7. As an article of inanu'l'aclure. a spring for time pieces composed oftantalum and carbon.

In witness whereof, l have hereunto subscribed my-nuinc this third dayof l el ruar wnnmm v. norxrox.

' Witnesses:

WoLonimn l lAUP'l, HENRY ITASIER.

